Treatment of plates for storage batteries



Patented Nov. 17, 1925.

UNITED STATES PATENT OFFICE.

No Drawing.

To all whom it may concern:

Be it known that I, CAMPBELL C. CARPEN- TEE, a citizen of the United States, residing at Niagara Falls, in the county of Niagara and State of New York, have invented new and useful Improvements in the Treatment of Plates for Storage Batteries, of which the following is a specification.

This invention, relates to treatment of plates for storage batteries.

'An object of the invention is to facilitate the handling of freshly pasted plates.

A further object of the invention is to prevent an excess of scrap in plate manufacturing.

A further object of the invention is to provide an improved method of hardening the surface of a freshly pasted plate.

Various methods have been devised for treatment of freshly pasted plates having for their objects the hardening of the plate surface to facilitate handling and to prevent loss of active material from the grid during subsequent operations of the plates. A popular method has been to dip the freshly pasted plate .in sulphuric acid. It has been found, however, that this causes excessive scrap, due to the fact that the sulphuric acid changes the surface of the plate to lead sulphate and leaves a distinct line of cleavage between the sulphate and. oxide of the active material. Probably due to the formation of gas, this thin lead sulphate layer is very aptto separate from the oxide and peel off, thus destroying the value of the plate.

In describing the present invention, reference is made to the details of the process which represents the best embodiment of the invention so far determined. It is not intended, however, that the specific description shall be construed except as illustrating this preferred embodiment, as it is obvious that changes may be made in details without departing from the spirit of the invention as set forth in the appended claims.

According to the present invention, the freshly pasted plates are passed between rubber covered rolls, preferably in a vertical direction, and a stream of sulphuric acid,

Application filed June 22, 1923.

Serial No. 647,191.

preferably of approxin lately 1.400 specific gravit is applied at the rolls on both sides of the plate, the rolls exerting pressure on the plate at the same time that the acid is applied. As a subsequent step the plates may be dried over a steam table or in a suitable oven at approximately 212 F. for a period of approximately fifteen minutes. This latter step will additionally harden the plate surface but is not essential, as bene ficial results are obtained from the simultaneous application of acid and pressure alone.

It has been found that plates so treated do not show the same distinct line of cleavage between the sulphate and oxide as is found in the dipping process and may be handled in the subsequent operations of battery manufacture without excessive damage and scrap.

What I claim as new and desire to secure by Letters Patent of the United States is- 1. A process for treating storage battery plates which comprises applying sulphuric acid to the surface of the plate and simultaneously applying a rolling pressure to the plate surface.

2. A process of treating battery plates which comprises passing freshly pasted plates in a vertical direction between r'olls exerting a yielding pressure on the plate surface and simultaneously applying sulphuric acid to the surface.

3. A process of treating battery plates which comprises passing the freshly pasted plates in a vertical direction between rubber rolls under pressure and simultaneously applying sulphuric acid of approximately 1.400 specific gravity on both sides of the plate.

4. A process of treating battery plates which comprises simultaneously applying sulphuric acid and pressure to the plate surfaces and subsequently drying the plate by the action of heat.

In witness whereof, I have hereunto subscribed my name.

CAMPBELL G. CARPENTER. 

